Photolithography is one of important processes in fabricating processing of a semiconductor device. When a foreign material is attached on a photo mask in photolithography, a pattern cannot be precisely transferred. Accordingly, a pellicle is attached on the photo mask to protect a pattern surface of the photo mask. The pellicle has a predetermined distance to the pattern surface of the photo mask. As a result, an image of the foreign material is not transferred in the exposure process even when the foreign material is attached on the pellicle.
However, in a trend of miniaturization of the semiconductor device, distortion of the photo mask after attaching the pellicle has been recognized as a problem. The distortion of the photo mask may be generated due to distortion of a pellicle frame. On the other hand, the photo mask itself may have distortion. Distortion may be generated in the photo mask after the photo mask is chucked on a photo mask chuck of an exposure apparatus.
In such a manner, a pattern cannot be precisely transferred when the exposure process is performed in a state of the photo mask with distortion. Accordingly, a method for transferring precisely a pattern is desirable.